Efforts at development of mathematical techniques for medical diagnosis have been confined to small areas of medical specialties in which observations on a limited set of variables are used to make a differential diagnosis between a limited number of mutually exclusive disease categories. The only exception to this is the technique proposed by Brodman and van Woerkom which is capable of assigning several categories to one patient, on the basis of the patient's response to a short version of the Cornell Medical Index. Using several statistical methods, we wish to explore the performance of automated diagnosis in the context of multiphasic screening, which ranges over a large area of medicine and involves both questionnaire and automated laboratory tests. On a data base of some 26,000 multiphasic records accumulated within one year, a pilot study has shown that it is possible to obtain the performance characteristics (plot of sensitivity against specificity) of a variety of techniques, such as the likelihood Ratio Method of Neyman or a Scoring System derived from that of Brodman and van Woerkom, within 3 minutes of computing time. Thus it has become practicable to compare not only different analytical techniques for a given disease and its set of variables but to repeat the inquiry over a variety of disease conditions sufficiently large to get a general idea concerning the potential of a diagnostic support system which goes beyond the current level of providing the clinician with the "basic" information only.